Metallic silver has many different applications because of its high electrical conductivity and reflectivity of infrared light. For example, metallic silver layers are frequently used in low emissivity (low-E) glass coatings. The thermal efficiency of window glass may be significantly improved by applying one or more silver reflective layers that do not let some of radiant infrared energy pass through the glass. As such, the radiant heat is kept on the same side of the glass from which it originated, while letting visible light pass. This effect results in more efficient windows because radiant heat originating from indoors in winter is reflected back inside preserving the heat where it is needed. On the other hand, the infrared heat generated by the sun during summer is reflected away, keeping the inside of the building cooler.